1. Field of the Invention
The present invention relates to a grinding and/or cutting endless belt which is adapted to grind or cut precise or minute parts such as optical parts, magnetic heads, semiconductor devices and so on.
2. Description of the Prior Art
Conventionally, for cutting or grinding precise or minute optical parts, for example, optical fiber connector, a wheel type grindstone has been used in general. The end surface of such an optical fiber connector to be ground is pressed onto a rotating surface of the wheel type grindstone. However, in such a grinding wheel, the grinding speed varies in accordance with the distance from the axis of the grinding wheel. Namely, the larger the distance from the axis is, the higher the grinding speed is. Thus, even if the location of the optical fiber connector slightly deviates in the radial direction of the grinding wheel, it varies that the ground depth of the end surface of the optical fiber connector in a predetermined time. As a result, the ground depth of each optical fiber connector becomes unequal and so these connectors are difficult to be precisely coupled with each other.
Besides, such a wheel type grindstone has need of a drive shaft at the center thereof. For this configuration, the grindstone itself needs to be large-sized and so large driving force is required. Furthermore, in such a wheel type grindstone, since only a predetermined part thereof must be used for uniform grinding as described above, the grindstone is consumed only in part. The large driving force and partial consumption result raising the cost of the optical fiber device.
On the other hand, a grinding endless belt and a cutting endless belt (a band saw) have been known. The conventional grinding belt has a paper or cloth base on which, for example, diamond abrasive grains are supported with an adhesive agent. However, in such known grinding endless belt, the bonds of the abrasive grains are very small and further only one layer of diamond abrasive grains is provided. Thus, the life of the grinding belt of this type is very short. The grinding belt of this type is originally for rough grinding and unsuitable for precise processing because of the small bonds of the abrasive grains.
The band saw comprises a steel belt and a large number of diamond chips attached to the edge of the steel belt. Such a band saw is only for cutting and can not be used for grinding. Furthermore, in the band saw, since each diamond chip is made of metal bonded grindstone, it is difficult to form diamond chips of small thickness, specifically, below 0.3 mm. Therefore, with the band saw, the cutout width of an article to be cut is considerably large and far more than 0.3 mm. For this reason, the conventional band saw is also unsuitable for precise processing.